1. Field of the Invention
The present invention relates to power supply systems and more particularly, to a high-power induction-type power supply system and its bi-phase decoding method that allows synchronous transmission of power supply and data signal and automatically regulates the power at the supplying-end coil and the power at the receiving-end coil. By means of bi-phase data decoding, data can be accurately decoded during full load of the receiving-end module, assuring high stability of the operation of the system.
2. Description of the Related Art
Following fast development of electronic and internet technology, many digitalized electronic products, such as digital camera, cellular telephone, multimedia player (MP3, MP4) and etc., have been continuously developed and have appeared on the market. These modern digital electronic products commonly have light, thin, short and small characteristics. However, for high mobility, power supply is an important factor. A mobile digital electronic product generally uses a rechargeable battery to provide the necessary working voltage. When power low, the rechargeable battery can be recharged. For charging the rechargeable battery of a digital electronic product, a battery charger shall be used. However, it is not economic to purchase a respective battery charger when buying a new mobile electronic product. Further, when one spends a large amount of money to purchase different mobile electronic products, a special storage space is necessary for the storage of the mobile electronic products. Further, it is inconvenient to carry and store many different mobile electronic products and the related battery chargers. Further, it takes much time to find one specific battery charger from a storage group of battery chargers.
Further, when using a battery charger to charge a mobile electronic apparatus, the user must connect the connection interface (plug) of the battery charger to an electric outlet and then connect the connector at the other end of the battery charger to the mobile electronic apparatus, enabling the mobile electronic apparatus to be charged. After charging, the mobile electronic apparatus is disconnected from the battery charger. As conventional battery chargers must be used where an electric outlet is available, the application of conventional battery chargers is limited. When in an outdoor space, conventional battery chargers cannot be used for charging mobile electronic apparatuses.
Further, except battery charging, a mobile electronic apparatus may need to make setting of related functions, data editing or data transmission. A user may directly operate the mobile electronic apparatus to make function setting or to input data. However, some mobile electronic apparatus (such as MP3 player, MP4 player, digital camera, electronic watch, mobile game machine, wireless game grip, wireless controller) do not allow direct setting or data transmission. When making function setting or data transmission, an external electronic device (computer, PDA) must be used. Further, when charging a mobile electronic apparatus, it may be not operable to transmit data. Further, wireless induction power supply systems (or the so-called wireless chargers) are commercially available. These wireless induction power supply systems commonly use two coils, one for emitting power supply and the other for receiving power supply. However, the energy of wireless power supply is dangerous and will heat metal objects. They work like an electromagnetic stove. The use of a wireless induction power supply system has the risk of overheat damage of the charged device.
Further, to ensure the safe operation of a wireless induction power supply system, power supplying operation can be started only after ID recognition between the supplying-end module and the receiving-end module. Under the requirement of this function, it is necessary to establish a data code transmission method for data transmission between the supplying-end module and the receiving-end module in a stable manner. According to conventional designs, the load at the receiving-end coil is modulated and fed back to the supplying-end coil, and a sensing circuit senses the variation of the signal and then picks up the data code by means of a predetermined decoding procedure. This method is applicable only when the load at the power output terminal of the receiving-end module is stable. If the load at the power output terminal of the receiving-end module is changed, the aforesaid method becomes not applicable. Because the load at the power output terminal of the receiving-end module affects the modulated signal at the receiving-end module, the transmission of the data code will be unstable.
Further, when the power output of the receiving-end module is fully loaded, the change of the output impedance causes a polarity change at the supplying-end module. After a change of the polarity, the supplying-end module becomes unable to demodulate the signal, causing interruption of the transmission of the control data and affecting normal functioning of the charging operation.
Therefore, it is desirable to a high-power induction-type power supply system that eliminates the problem of data code transmission instability during a synchronous charging and data transmission operation and the problem of data signal transmission interruption due to a load characteristic change between the supplying-end module and the receiving-end module during a synchronous charging and data transmission operation.